I already wrote about this before but the question was asked again so I answered it.

"How would you know if there was a God or not?"

There is something called "common sense".

How would I know the Easter Bunny is not real? Common sense tells me the magic rabbit is impossible.

It's exactly the same for the magic god fairy fantasy. The thing is impossible. There is no magic in the universe.

This is not rocket science. Any unbrainwashed child could figure it out.